全文获取类型
收费全文 | 282篇 |
免费 | 7篇 |
出版年
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 7篇 |
2015年 | 12篇 |
2014年 | 13篇 |
2013年 | 11篇 |
2012年 | 26篇 |
2011年 | 22篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 26篇 |
2007年 | 18篇 |
2006年 | 16篇 |
2005年 | 13篇 |
2004年 | 10篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1998年 | 5篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有289条查询结果,搜索用时 187 毫秒
71.
72.
Y. Hotta Keiko Fujiki Mutsuko Hayakawa Takashi Ohta Takuro Fujimaki Kouichi Tamaki Toshiyuki Yokoyama Atsushi Kanai Akito Hirakata Tetsuo Hida Sachiko Nishina Noriyuki Azuma 《Human genetics》1998,103(2):142-144
We investigated the XLRS1 gene in Japanese patients with retinoschisis (RS). All exons of the XLRS1 gene were sequenced in 14 males, including a pair of monozygotic twins, from 11 individual families with RS and five of their
mothers who are asymptomatic but diagnosed as carriers. Six kinds of missense mutations and a nonsense mutation, including
six novel mutations, were detected in all 14 patients and carriers. Mutations in the XLRS1 gene are also responsible for RS in non-Caucasian patients. Most Japanese RS cases are caused by an XLRS1 gene defect. A novel mutation, Glu72Lys, was found in four families, suggesting a common mutation in the Japanese population.
Clinical features of RS patients with both the Glu72Lys and Pro193Leu mutations indicate that a genotype–phenotype correlation
is not recognized in RS.
Received: 12 January 1998 / Accepted: 21 March 1998 相似文献
73.
Mallotus roxburghianus is used in the traditional medicine in North-Eastern India, but previously no work has been done on the identification of bioactive compounds. Two new compounds, 3-(1-C-beta-D-glucopyranosyl)-2,6-dihydroxy-5-methoxybenzoic acid (6) and 2,4,8,9,10-pentahydroxy-3,7-dimethoxyanthracene-6-O-beta-D-rhamnopyranoside (7) together with beta-sitosterol (1), stigmasterol (2), betulinic acid (3), 4-hydroxybenzoic acid (4), beta-sitosterol-beta-D-glucoside (5), and bergenin (8) were isolated and identified from the leaves of M. roxburghianus. The chloroform soluble portion of the alcoholic extract of leaf, and compounds 3, 6, 7, and 8 exhibited encouraging antioxidant activities. 相似文献
74.
Tanaka R Sakano Y Nagatsu A Shibuya M Ebizuka Y Goda Y 《Bioorganic & medicinal chemistry letters》2005,15(1):159-162
Digalactosyl and monogalactocyl diacylglycerols (DGDG and MGDG), which were identified as anti-hyperlipemia active components in Colocasia esculenta (Taro), were synthesized. The inhibitory activity of DGDG, MGDG and related compounds on human lanosterol synthase was evaluated as anti-hyperlipemic activity. DGDG with two myristoyl groups at both sn-1 and sn-2 positions and with an oleoyl group at the sn-1 position showed the most potent activity. 相似文献
75.
Zebrafish and goldfish are both diurnal freshwater fish species belonging to the same family, Cyprinidae, but their visual ecological surroundings considerably differ. Zebrafish are surface swimmers in conditions of broad and shortwave-dominated background spectra and goldfish are generalized swimmers whose light environment extends to a depth of elevated short wavelength absorbance with turbidity. The peak absorption spectrum (lambdamax) of the zebrafish blue (SWS2) visual pigment is consistently shifted to short wavelength (416 nm) compared with that of the goldfish SWS2 (443 nm). Among the amino acid differences between the two pigments, only one (alanine in zebrafish and serine in goldfish at residue 94) was previously known to cause a difference in absorption spectrum (14-nm lambdamax shift in newt SWS2). In this study, we reconstructed the ancestral SWS2 pigment of the two species by applying likelihood-based Bayesian statistics and performing site-directed mutagenesis. The reconstituted ancestral photopigment had a lambdamax of 430 nm, indicating that zebrafish and goldfish achieved short wavelength (-14 nm) and long wavelength (+13 nm) spectral shifts, respectively, from the ancestor. Unexpectedly, the S94A mutation resulted in only a -3-nm spectral shift when introduced into the goldfish SWS2 pigment. Nearly half of the long wavelength shift toward the goldfish pigment was achieved instead by T116L (6 nm). The S295C mutation toward zebrafish SWS2 contributed to creating a ridge of absorbance around 400 nm and broadening its spectral sensitivity in the short wavelength direction. These results indicate that the evolutionary engineering approach is very effective in deciphering the process of functional divergence of visual pigments. 相似文献
76.
Mice with altered alpha(1)-adrenergic receptor (AR) genes have become important tools in elucidating the subtype-specific functions of the three alpha(1)-AR subtypes because of the lack of sufficiently subtype-selective pharmacological agents. Mice with a deletion (knockout, KO) or an overexpression (transgenic, TG) of the alpha(1A)-, alpha(1B)-, or alpha(1D)-AR subtypes have been generated. The alpha(1)-ARs are the principal mediators of the hypertensive response to alpha(1)-agonists in the cardiovascular system. Studies with these mice indicate that alpha(1A)-AR and alpha(1B)-AR subtypes play an important role in cardiac development and/or function as well as in blood pressure (BP) response to alpha(1)-agonists via vasoconstriction. The alpha(1B)- and alpha(1D)-subtypes also appear to be involved in central nervous system (CNS) processes such as nociceptive responses, modulation of memory consolidation and working memory. The ability to study subtype-specific functions in different mouse strains by altering the same alpha(1)-AR in different ways strengthens the conclusions drawn from these studies. Although these genetic approaches have limitations, they have significantly increased our understanding of the functions of alpha(1)-AR subtypes. 相似文献
77.
Mun Sup Yoon Koji Doi Akito Kaga Norihiko Tomooka Duncan A Vaughan 《Journal of plant research》2000,113(4):375-386
Vigna subgenus Ceratotropis (V. angularis, V. minima, V. nakashimae, V. reflexo-pilosa, V. riukiuensis and V. umbellata) was investigated using AFLP methodology. Species in the V. minima complex, V. minima, V. nakashimae and V. riukiuensis, had greater intra-specific polymorphism than the other species analyzed. Vigna species from East Asia analysed could be clearly distinguished. The relationship between species was consistent using different
analyses and showed V. riukiuensis and V. nakashimae are closely related. The phenetic distance between species (1-Jaccard's similarity coefficient) ranged from 0.279 between
V. riukiuensis and V. nakashimae to 0.688 between V. reflexo-pilosa and V. minima. Genetic distance based on inferred nucleotide diversity (π) ranged from 0.012 between V. riukiuensis and V. nakashimae and 0.053 between both V. riukiuensis and V. nakashimae and V. reflexo-pilosa. The diversity (Ha) within species, based on Shannon's information index of phenotypic diversity, was lowest in V. reflexo-pilosa (0.006) and highest in V. minima (0.095). Korean and Japanese populations of V. nakashimae had distinct polymorphism. Vigna riukiuensis populations from Miyako island were genetically different from populations of other islands of southern Okinawa.
Received 21 April 2000/ Accepted in revised form 5 September 2000 相似文献
78.
Emmanuel F.A. Toussaint Roger Vila Masaya Yago Hideyuki Chiba Andrew D. Warren Kwaku Aduse‐Poku Caroline Storer Kelly M. Dexter Kiyoshi Maruyama David J. Lohman Akito Y. Kawahara 《Systematic Entomology》2019,44(4):926-938
The origin of taxa presenting a disjunct distribution between Africa and Asia has puzzled biogeographers for more than a century. This biogeographic pattern has been hypothesized to be the result of transoceanic long‐distance dispersal, Oligocene dispersal through forested corridors, Miocene dispersal through the Arabian Peninsula or passive dispersal on the rifting Indian plate. However, it has often been difficult to pinpoint the mechanisms at play. We investigate biotic exchange between the Afrotropics and the Oriental region during the Cenozoic, a period in which geological changes altered landmass connectivity. We use Baorini skippers (Lepidoptera, Hesperiidae) as a model, a widespread clade of butterflies in the Old World tropics with a disjunct distribution between the Afrotropics and the Oriental region. We use anchored phylogenomics to infer a robust evolutionary tree for Baorini skippers and estimate divergence times and ancestral ranges to test biogeographic hypotheses. Our phylogenomic tree recovers strongly supported relationships for Baorini skippers and clarifies the systematics of the tribe. Dating analyses suggest that these butterflies originated in the Oriental region, Greater Sunda Islands, and the Philippines in the early Miocene c. 23 Ma. Baorini skippers dispersed from the Oriental region towards Africa at least five times in the past 20 Ma. These butterflies colonized the Afrotropics primarily through trans‐Arabian geodispersal after the closure of the Tethyan seaway in the mid‐Miocene. Range expansion from the Oriental region towards the African continent probably occurred via the Gomphotherium land bridge through the Arabian Peninsula. Alternative scenarios invoking long‐distance dispersal and vicariance are not supported. The Miocene climate change and biome shift from forested areas to grasslands possibly facilitated geodispersal in this clade of butterflies. 相似文献
79.
Kosuke Fujita Katsunori Kuge Noriyasu Ozawa Shunya Sahara Kaori Zaiki Koichi Nakaoji Kazuhiko Hamada Yukiko Takenaka Takao Tanahashi Katsuto Tamai Yasufumi Kaneda Akito Maeda 《PloS one》2015,10(12)
Substances that enhance the migration of mesenchymal stem cells to damaged sites have the potential to improve the effectiveness of tissue repair. We previously found that ethanol extracts of Mallotus philippinensis bark promoted migration of mesenchymal stem cells and improved wound healing in a mouse model. We also demonstrated that bark extracts contain cinnamtannin B-1, a flavonoid with in vitro migratory activity against mesenchymal stem cells. However, the in vivo effects of cinnamtannin B-1 on the migration of mesenchymal stem cells and underlying mechanism of this action remain unknown. Therefore, we examined the effects of cinnamtannin B-1 on in vivo migration of mesenchymal stem cells and wound healing in mice. In addition, we characterized cinnamtannin B-1-induced migration of mesenchymal stem cells pharmacologically and structurally. The mobilization of endogenous mesenchymal stem cells into the blood circulation was enhanced in cinnamtannin B-1-treated mice as shown by flow cytometric analysis of peripheral blood cells. Whole animal imaging analysis using luciferase-expressing mesenchymal stem cells as a tracer revealed that cinnamtannin B-1 increased the homing of mesenchymal stem cells to wounds and accelerated healing in a diabetic mouse model. Additionally, the cinnamtannin B-1-induced migration of mesenchymal stem cells was pharmacologically susceptible to inhibitors of phosphatidylinositol 3-kinase, phospholipase C, lipoxygenase, and purines. Furthermore, biflavonoids with similar structural features to cinnamtannin B-1 also augmented the migration of mesenchymal stem cells by similar pharmacological mechanisms. These results demonstrate that cinnamtannin B-1 promoted mesenchymal stem cell migration in vivo and improved wound healing in mice. Furthermore, the results reveal that cinnamtannin B-1-induced migration of mesenchymal stem cells may be mediated by specific signaling pathways, and the flavonoid skeleton may be relevant to its effects on mesenchymal stem cell migration. 相似文献
80.
Eisenhardt SU Habersberger J Oliva K Lancaster GI Ayhan M Woollard KJ Bannasch H Rice GE Peter K 《Proteome science》2011,9(1):1-12